Fixed some nasty issues with trying to use imguigml_image with surfaces... it potentially could access texture pointers that were no longer valid - so I've added the new imguigml_surface call that helps ensure the surface exists before we try to draw it.

Stay tuned for more control over when ImGuiGML draws (Draw vs DrawGUI) and more fixes!

Changelist for version 1.2.3

• API
  • Added imguigml_surface and refactored how sprite and 'image' works. imguigml_image still takes a texture pointer, but there's rarely a reason to use it.
• Fixes:
  • Fixed draw_add_rect_filled
  • Automatically multiply the normalized pixel percent trimmed from sprites when useing imguigml_sprite
  • imguigml_button now accepts 1 param for size
  • Fix imguigml_color_convert_ gml / u32 functions being backwards